Fish 101

Updated:Aug 17,2015

Fish is a good source of protein and, unlike fatty meat products, it’s not high in saturated fat. Fish is also a good source of omega-3 fatty acids. Omega-3 fatty acids benefit the heart of healthy people and those at high risk of — or who have — cardiovascular disease. Research has shown that omega-3 fatty acids decrease risk of arrhythmias (abnormal heartbeats), which can lead to sudden cardiac death. Omega-3 fatty acids also decrease triglyceride levels, slow the growth rate of atherosclerotic plaque and lower blood pressure (slightly).

We recommend eating fish (particularly fatty fish) at least two times (two servings) a week. Each serving is 3.5 oz. cooked, or about ¾ cup of flaked fish. Enjoy fish baked or grilled, not fried. Choose low-sodium, low-fat seasonings such as spices, herbs, lemon juice and other flavorings in cooking and at the table.

Fatty fish like salmon, mackerel, herring, lake trout, sardines and albacore tuna are high in two kinds of omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have demonstrated benefits at reducing heart disease.

We also recommend eating tofu and other forms of soybeans, canola, walnut and flaxseed, and their oils. These foods contain alpha-linolenicacid (ALA), another omega-3 fatty acid. Large-scale epidemiologic studies suggest that people at risk for coronary heart disease benefit from consuming omega-3 fatty acids from marine and plant sources. However, more studies are needed to show a cause-and-effect beneficial relationship between ALA and heart disease.

Increasing omega-3 fatty acid consumption through foods is preferable. However, coronary artery disease patients may not be able to get enough omega-3 by diet alone. These people may want to talk to their doctor about taking a supplement. Supplements also could help people with high triglycerides, who need even larger doses.

Population

Recommendation

Patients without documented coronary heart disease (CHD)

Eat a variety of (preferably fatty) fish at least twice a week. Include oils and foods rich in alpha-linolenic acid (flaxseed, canola and soybean oils; flaxseed and walnuts).

Patients with documented CHD

Consume about 1 g of EPA+DHA per day, preferably from fatty fish. EPA+DHA in capsule form could be considered in consultation with the physician.

Patients who need to lower triglycerides

2 to 4 grams of EPA+DHA per day provided as capsules under a physician’s care.

Patients taking more than 3 grams of omega-3 fatty acids from capsules should only do so under a physician’s care. High intakes could cause excessive bleeding in some people.

Some types of fish may contain high levels of mercury, PCBs (polychlorinated biphenyls), dioxins and other environmental contaminants. Levels of these substances are generally highest in older, larger predatory fish and marine mammals.

The benefits and risks of eating fish vary depending on a person’s stage of life.

Children and pregnant women are advised by the U.S. Food and Drug Administration (FDA) to avoid eating those fish with the potential for the highest level of mercury contamination (e.g., shark, swordfish, king mackerel or tilefish); to eat up to 12 ounces (two average meals) per week of a variety of fish and shellfish that are lower in mercury (e.g., canned light tuna, salmon, pollock, catfish); and to check local advisories about the safety of fish caught by family and friends in local lakes, rivers and coastal areas.

For middle-aged and older men and postmenopausal women, the benefits of eating fish far outweigh the potential risks when the amount of fish are eaten is within the recommendations established by the FDA and Environmental Protection Agency.

Eating a variety of fish will help minimize any potentially adverse effects due to environmental pollutants.

Potential exposure to some contaminants can be reduced by removing the skin and surface fat from these fish before cooking. Consumers should also check with local and state authorities about types of fish and watersheds that may be contaminated and visit the FDA website for the most up-to-date information on recommendations for specific subgroups of the U.S. population (e.g., children, pregnant women).

Five of the most commonly eaten fish or shellfish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish. Avoid eating shark, swordfish, king Mackerel, or tilefish because they contain high levels of mercury.